Automatically set precision when bootstrap resampling is used

app/Main.hs

@@ -5,12 +5,11 @@ import GEval.EvaluationScheme
 import GEval.Common
 import GEval.OptionsParser
 import GEval.ParseParams
+import GEval.Formatting
 
 import System.Environment
 import Options.Applicative
 
-import Text.Printf
-
 import System.IO
 import System.Exit
 
@@ -112,17 +111,3 @@ formatSourceSpec spec = show spec
 
 formatTheMetricAndResult :: Maybe Int -> (EvaluationScheme, MetricResult) -> String
 formatTheMetricAndResult mPrecision (scheme, val) = (evaluationSchemeName scheme) ++ "\t" ++ (formatTheResult mPrecision val)
-
-
-formatTheResult :: Maybe Int -> MetricResult -> String
-formatTheResult mPrecision (SimpleRun val) = formatSimpleResult mPrecision val
-formatTheResult mPrecision (BootstrapResampling vals) = (formatSimpleResult mPrecision pointEstimate)
-                                                        ++ "±"
-                                                        ++ (formatSimpleResult mPrecision errorBound)
-    where pointEstimate = (upperBound + lowerBound) / 2.0
-          errorBound = (upperBound - lowerBound) / 2.0
-          (lowerBound, upperBound) = getConfidenceBounds defaultConfidenceLevel vals
-
-formatSimpleResult :: Maybe Int -> MetricValue -> String
-formatSimpleResult Nothing = show
-formatSimpleResult (Just prec) = printf "%0.*f" prec

geval.cabal

@@ -52,6 +52,7 @@ library
                      , Data.CartesianStrings
                      , Data.SplitIntoCrossTabs
                      , Data.Conduit.Bootstrap
+                     , GEval.Formatting
                      , Paths_geval
   build-depends:       base >= 4.7 && < 5
                      , cond

src/GEval/Formatting.hs

@@ -0,0 +1,27 @@
+module GEval.Formatting
+       (formatTheResult, formatSimpleResult)
+       where
+
+import GEval.Common
+import Data.Conduit.Bootstrap
+import Text.Printf
+
+
+formatTheResult :: Maybe Int -> MetricResult -> String
+formatTheResult mPrecision (SimpleRun val) = formatSimpleResult mPrecision val
+formatTheResult mPrecision (BootstrapResampling vals) = (formatSimpleResult correctedPrecision pointEstimate)
+                                                        ++ "±"
+                                                        ++ (formatSimpleResult correctedPrecision errorBound)
+    where pointEstimate = (upperBound + lowerBound) / 2.0
+          errorBound = (upperBound - lowerBound) / 2.0
+          (lowerBound, upperBound) = getConfidenceBounds defaultConfidenceLevel vals
+          errorBoundMagnitude = (floor (logBase 10.0 errorBound)) - 1
+          correctedPrecision = Just $ selectLowerPrecision (max (-errorBoundMagnitude) 0) mPrecision
+
+formatSimpleResult :: Maybe Int -> MetricValue -> String
+formatSimpleResult Nothing = show
+formatSimpleResult (Just prec) = printf "%0.*f" prec
+
+selectLowerPrecision :: Int -> Maybe Int -> Int
+selectLowerPrecision p Nothing = p
+selectLowerPrecision p (Just p') = min p p'